Expandable bushing for well casing hangers



Dec. 10, 1968 s. w. PUTCH 3,415,322

EXPANDABLE BUSHING FOR WELL CASING HANGERS Filed Oct. 14, 1966 I: SheetsShe'et 2 Q Q ON w V@ A \NN 0% mm mm .3 W N M ww ,9 Nm Nm fi\ mm k vm QM NP A m H 1| m H PMHI INVENTOR sm w. PUTOH ATTORNEY 3 Sheets-Sheet 3 S. W. PUTCH EXPANDABLE BUSHING FOR WELL CASING HANGERS Dec. 10, 1968 Filed Oct. 14.

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WW 3 8 \|m Nm v mm Om wm @m mp L INVENTOR. SAM W. PUTOH f ma-A [11W ATTORNEY v United States Patent Office 3,415,322 Patented Dec. 10, 1968 3,415,322 EXPANDABLE BUSHING FOR WELL CASING HANGERS Sam W. Putch, Houston, Tex., assiguor to FMC Corporation, San Jose, Calif., a corporation of Delaware Filed Oct. 14, 1966, Ser. No. 586,702 8 Claims. (Cl. 166-217) ABSTRACT OF THE DISCLOSURE An apparatus for supporting a string of casing in a Well, including a specially-shaped landing sub and a radiallyexpandable tubular bushing that can be locked in the sub by rotation in one direction to provide a casing support, and passed through the sub by rotation in the opposite direction when the casing support is desired at another level of the well.

This invention relates to a well tool for supporting strings of well casing. More particularly, this invention relates to a bushing which can be expanded into a selected sub or nipple positioned in a well casing to provide support for a hanger for smaller diameter casing strings.

The usual process of drilling a well for the recovery of oil, gas, or other fluids involves lining the well bore with sections or strings of tubular casing of progressively smaller diameter to prevent the bore from caving, to forestall entry of undesirable fluids, to enhance production operations, and for various other reasons. It is very important that the outermost or surface casing be firmly anchored or set in a competent or structurally sound and strong formation, for the surface casing also acts as a foundation for all the other casing strings which, in a well based on firm ground, are all anchored to its top or head. However, when drilling at off-shore locations or on swampy or otherwise unsound land, the water and the adjacent underlying earth formations through which the surface casing must extend provide it with practically no support, and it must be driven into deeper competent formations until the needed support is found. That unsupported portion of the surface casing between the deeper competent formation and the wellhead is subject to considerable stress and strain, especially in a lateral direction as a result of water motion, and placing the additional burden of the weight of the inner casing strings upon this portion greatly increases the danger of it collapsing.

To overcome this problem the practice has been to anchor the casing strings to the surface casing as close as possible to the area where the surface casing is adequately supported by a competent formation. Since it usually is not possible to accurately foretell where this area will be, and thus how much casing will be required to reach it, a difiicult problem exists in properly prepositioning a casing string anchoring device or hanger in the surface casing before running it in the well. On the other hand, installing a casing hanger after the surface casing has been set in the competent formation can be equally difficult even with the best tools heretofore available.

The foregoing problems are overcome by the present invention which, in summary, involves a new type of expandable casing hanger bushing and a landing sub especially adapted to receive the bushing and either hold it so that it can in turn provide support for an inner casing string, or permit it to pass through and on to another more desirable level in the well. Whether the bushing is held in or passes through the sub is dependent upon the direction in which the bushing is rotated, so that by including a plurality of subs spaced at selected intervals in the outer casing, the inner casing can be hung at any chosen level in the well. This facility for holding or passing the bushing results from a novel connection between the bushing and the sub, and includes a plurality of external ears radially projecting from the bushing to contact with a pair of annular shoulders, and a slot and groove pathway through the shoulders with stops to control the extent of rotation of the: bushing in either direction.

Accordingly, an object of the present invention is to provide a new system for accurately positioning and securely anchoring well casing strings to a surface casing.

Another object of the present invention is to provide a new system for positioning a well casing hanger at any of a number of pre-established locations in a surface casing after the surface casing has been set.

Another object of the present invention is to provide a bushing and a cooperating landing sub for anchoring a casing string hanger to a surface casing, which bushing can be easily positioned in the sub at the desired location after the surface casing has been set.

Still another object of the present invention is to provide an expandable bushing for supporting inner casing hangers inside an outer well casing, and a landing sub adapted for connecting into the outer casing and receiving the bushing which can be run in the well and set in the sub with drill pipe or other conventional well drilling equipment.

Yet another object of this invention is to provide an expandable casing hanger bushing which can be set in its landing sub by a simple rotating motion.

A still further object of the present invention is to pro- -vide a new procedure for positioning an inner casing string anchor device at a desired location in a surface casing.

The foregoing as well as further objects and advantages of the present invention will become readily apparent from the following description of a device constructed in accordance therewith, and from the accompanying drawings thereof, in which:

FIGURE 1 is a view in side elevation, and partially in section, of an expandable bushing and its cooperating landing sub according to this invention, the sub positioned between two lengths of well casing and the bushing resting in the casing above the sub;

FIGURE 2 is another view of the bushing and sub of FIGURE 1, showing the bushing after :it has been lowered into the sub from its position in FIGURE 1, and before it has been rotated and expanded into locking engagement with the sub;

FIGURE 3 is a view in cross-section, taken along the line 3-3 of FIGURE 2, showing the positions of the bushings landing ears in relation to the slots and stop pins on the sub;

FIGURE 4 is a view of the bushing and sub of FIG- URES l and 2, showing the bushing after it has been rotated clockwise and set in the sub, and also showing the running tool after it has been withdrawn from the bushing; and

FIGURE 5 is a view similar to FIGURES l, 2 and 4, showing the bushing after it has been rotated counterclockwise, partially passed through the sub, and positioned for lowering further into the casing.

Broadly considered, as illustrated in the drawings the expandable bushing 10 of the invention comprises an elongate annular housing 12, an annular lock ring 14 slida'bly circumscribing and carried by the housing 12, an annular expander 16 rotatably circumscribing the housing 12, and an annular retainer ring 18 circumscribing and tightly gripping the housing 12 to retain the expander on the housing.

The expander 16 is threaded along a portion of its internal surface at 20, and the underlying portion of the external surface of the housing 12 has corresponding threads 22. Thus, rotating the housing 12 while the expander 16 is stationary will cause the housing to travel axially within the expander. The threads 20, 22 preferably are right handed so that when the housing 12 is rotated clockwise when viewed from above, i.e., in the direction of arrow C in FIGURE 3, the housing will move downwardly in the expander as indicated by the arrow in FIGURE 2.

The housing 12 has an annular retainer surface 24 upon which the lock ring 14 is carried in its retracted condition as shown in FIGURES 1, 2 and 5. From the upper edge of the retainer surface 24 an inclined annular expanding surface 26 extends upwardly and outwardly to an annular locking surface 28 of larger diameter than the retainer surface 24. A retainer flange 30 extends outwardly from the upper limit of the locking surface 28 to provide a stop against which the expandable lock ring 14 bears when it is in locking position on the surface 28 (FIG. 4).

The expandable bushing 10 is designed so that it can be removably attached to a drill string or other suitable pipe through a conventional running tool. This is implemented primarily by a plurality of shear pins 32 spaced equally around the upper end of the housing 12 and extending through ports in the housing into coinciding ports in a running tool 34, which tool is attached in a conventional manner to the drill string or pipe 36. Accordingly, when the expandable bushing 10 has been set in place (FIG. 4), the running tool 34 can be disconnected and recovered merely by lifting upon the drill string or pipe 36 and shearing the pins 32.

The expandable bushing 10 has been designed to cooperate with conventional running tools which contain a plurality (usually four) of equally spaced locking cars 38 that fit into corresponding slots and grooves in the well devices which they handle, and by rotating the tool and either lifting up or letting down on it the connection between the device and the tool can be broken or established, respectively. This is facilitated with the expandable bushing 10 by an inner annular groove 40 in the upper end of the housing 12, a plurality of slots 42 of equal spacing and number with the ears 38 on the running tool 34, and a like number of stop pins 44 (FIGURE 4; only one shown) projecting radially inward from the groove 40 and tangentially adjacent to the slots 42. Thus, when the running tool 34 is inserted into the housing 12 until the ears 38 are in the groove 40, and then rotated counterclockwise or to the left as indicated by arrows B (FIG. 1) and D (FIG. 3), the ears 38 will travel around the slot 40 and come to rest against the stop pins 44, locking the tool 34 in the housing 12. As shown by arrows A and C, clockwise rotation until the ears 38 come to rest against the opposite sides of the pins 44 places the ears 38 directly in line with the slots 42, and the tool 34 can then be withdrawn from the housing 12 by simply lifting it out. This system provides a secondary or back-up procedure for running in and setting the expandable bushing 10 in the event the shear pins 32 accidentally give way pre maturely.

The expandable bushing 10 and its landing sub are designed so that the bushing 10 can be either set or passed through the sub 50 as desired. The landing sub 50 is annular in shape and comprises a pair of spaced internal upper and lower shoulders 52, 54, respectively, defining between them a groove 56. The upper shoulder 52 has upper and lower beveled ledges 58, 60, and three slots 62 spaced 120 from each other. In similar manner, the lower shoulder 54 has upper and lower beveled ledges 64, 66, and three. slots 68 spaced 120 with respect to each other and with respect to the slots 62, as shown in FIGURE 1. Stop pins project radially inward from the groove 56 tangentially adjacent to the slots 68. The landing sub 50 is threaded internally at its upper end for connecting it to a length of well casing 72, and threaded exteriorly at its lower end for connecting it to a conventional casing coupling 74, which, in turn, is threadedly connected to another length of well casing 76.

As has been mentioned previously, the expandable bushing 10 can be set in the sub 50 by a simple rotating motion. The bushing 10 is lowered through the casing 72 until the landing cars which extend outwardly from the expander 16 contact the upper ledge 58 of the subs upper shoulder 52. Carrying the bushing 10 with it, the drill pipe is then rotated clockwise, i.e., to the right as shown by arrow A in FIGURE 1, until the ears 80 move over and drop through the slots 62, coming to rest on the upper ledge 64 of the subs lower shoulder 54 (FIGS. 2 and 3). The drill pipe and the bushing then are again rotated clockwise, as indicated by arrow C of FIGURE 3, until the ears 80 contact the subs stop pins 70 in the groove 56 and prevent further rotation of the expander 16. Continuing clockwise rotation of the drill pipe then rotates and threads the housing 12 into the expander 16 and forces the housings expanding surface 26 through the lock ring 14, camming the ring out onto the subs locking surface 28 and seating the housings stop flange 30 onto the rings upper surface. The running tool 34 is then removed by lifting up on the drill pipe as described above.

When it is desired to pass the bushing 10 through the sub 50, such as when several subs have been spaced in the casing in an effort to end up with at least One in the area where the casing is adequately supported by a competent formation, and the selected sub is beneath one or more upper subs, the bushing is lowered in the same way until the landing ears 80 contact the subs shoulder 52. The drill pipe is then rotated counter-clockwise or to the left (as shown by arrow B in FIG. 1) until the ears 80 drop through the slots 62 and continue in this direction around the slot 56 to contact the stop pins 70. At this position the ears 80 are directly above the slots 68 in the subs lower shoulder 54, and letting down on the drill pipe will let these ears pass through the slots (as shown in FIGURE 5) and on into the lower section of casing 76. The bushing can then be lowered to the next sub and either set or passed through it as desired.

Thus, merely by including a sufficient number of subs in the casing so that when the casing is set at least one of the subs is at or near enough to the desired competent formation, the bushing can be set at this formation regardless of its distance from the wellhead or the number of subs through which it must pass.

Although a rather flat, split-ring type of lock ring, a three slot-and-ear system, and a four-cared running tool have been described and illustrated, these may all be modified in various ways that will be apparent to those skilled in the art without departing from the scope of the invention.

Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention as set forth in the appended claims.

I claim:

1. An expandable bushing for providing support for well tools in a tubular housing, comprising:

(a) an elongate, annular housing having an external annular stop flange, an external annular retainer surface axially spaced beneath said stop flange and hav ing a first diameter, an external annular locking surface between said stop flange and said retainer surface and of a second diameter larger than said first diameter, and an external annular tapered expanding surface extending outwardly and upwardly from said retainer surface to said locking surface;

(b) an annular lock ring slidably circumscribing and carried by said housing beneath said stop flange and adapted to move axially from a normally contracted condition surrounding said retainer surface, over said expanding surface and onto said locking surface into an expanded and tool supportive condition;

(0) an annular expander rotatably circumscribing said housing and disposed beneath said lock ring;

(d) means for moving said expander axially on said housing; and

(e) an annular retainer ring circumscribing and gripping said housing beneath said expander.

2. The bushing of claim 1 wherein the expander contains a plurality of landing ears evenly and circumferentially spaced around its outer surface.

3. The bushing of claim 1 wherein the expander and the housing are threadedly interconnected such that rotating the housing while holding the expander stationary will move the housing axially in the expander.

4. The bushing of claim 1 wherein the housing is adapted for connection to a running tool through a shear pin system.

5. The bushing of claim 1 wherein the housing is adapted for connection to a running tool through a mating pin and slot system.

6. A landing sub for an expandable bushing for providing support for well tools in a tubular housing, comprising an annular sleeve with a pair of axially spaced, radially projecting, internal upper and lower annular shoulders having upper ledges adapted for supportinglanding ears on said expandable bushing, each of said shoulders having a plurality of evenly spaced axiallyextending slots for passing said bushing through said sub, the slots of said upper shoulder being offset circumferentially from the slots of said lower shoulder; and at least one stop means projecting radially inwardly from between said shoulders adjacent one of the slots in said lower shoulder and circumferentially spaced from the next adjacent upper shoulder slot, whereby when said expandable bushing is positioned in said sub with said ears between said shoulders and axially aligned with the slots in said upper shoulder, rotation of said bushing in one direction until an ear contacts said stop means will axially align said ears with the slots in said lower shoulder to thereby facilitate axial movement of said bushing past said lower shoulder, and rotation of said bushing in the opposite direction until an ear contacts said stop means will restrict said bushing against axial movement past either shoulder, thereby locking said bushing in said sub.

7. In combination, an expandable bushing for providing support for well tools in a tubular housing, and a landing sub for said bushing, said bushing comprising:

(a) an elongate, annular housing having an external annular stop flange, an external annular retainer surface axially spaced beneath said stop flange and having a first diameter, an external annular locking surface between said stop flange and said retainer surface and of a second diameter larger than said first diameter, and an external annular tapered expanding surface extending outwardly and upwardly from said retainer surface to said locking surface, said housing being adapted for connection to a running tool through a shear pin system and a mating pin and groove system;

(b) an annular lock ring slidably circumscribing and carried by said housing beneath said stop flange and adapted to move axially from a normally contracted condition surrounding said retainer surface, over said expanding surface and onto said locking surface into an expanded and tool supportive condition;

(c) an annular expander circumscribing said housing and disposed beneath said lock ring, said expander having a plurality of circumferentially-spaced landing ears extending outwardly from its outer surface, said expander being threadedly interconnected to said housing; and

(d) an annular retainer ring circumscribing and gripping said housing beneath said expander;

said landing sub having a pair of internal, radially projecting annular shoulders adapted to support said bushing, said shoulders having a plurality of circumferentiallyspaced axially-extending slots for receiving said ears to pass said bushing through said sub.

8. The combination bushing and sub of claim 7 wherein said shoulders of said sub contain a plurality of axially-extending, circumferentially-spaced slots corresponding to said landing ears on said bushing expander, said slots of one shoulder offset from said slots of the other shoulder, and a plurality of inwardly projecting stop pins between said shoulders positioned tangentially adjacent said slots of one shoulder.

References Cited UNITED STATES PATENTS 1,896,104 2/1933 Simmons 166242 X 2,011,769 8/1935 Leman 285402 X 2,851,108 9/1958 Reed 166139 2,862,560 12/1958 Bostock et a1 166-217 X 3,250,331 5/1966 Boyle 166217 X FOREIGN PATENTS 1,301,318 7/1962 France.

CHARLES E. OCONNELL, Primary Examiner. IAN A. CALVERT, Assistant Examiner.

US. Cl. X.R. 166-242; 285-141, 402 

